The present invention relates generally to filling pipe systems for introducing fuel into the fuel tank of an automotive vehicle. More particularly, the invention relates to an improved automotive fuel filling pipe system which is easily installed, lightweight and collision safe, and which provides automatic venting of overpressures within the fuel tank, while preventing the leakage of fuel and fuel vapors during normal operation and filling.
There have been numerous designs for fuel tank filler systems for automotive vehicles. With the advent of pollution control through vapor recovery systems and unleaded fuels, fuel filler pipes have become increasingly complex. This complexity arises from a number of design requirements. The fuel filling system must prevent leakage of fuel and vapor from the system in normal operation. It must allow for the entry of air to replace the fuel within the tank as it is consumes during use, and must also allow for the venting of overpressures within the tank, which can be caused by temperature changes, for example. The fuel filling pipe system must also provide a means for operating the automatic shut-off mechanism found on filling station fuel dispensing nozzles. In many jurisdictions, vapor recovery systems are required to prevent air pollution. In addition, the fuel filling pipe system must be capable of grounding out any static electric charge that may build up, and must also function over a wide range of ambient temperatures, both within the fuel tank system and external thereto. Finally, today's fuel filling pipe system must be constructed to prevent the introduction of leaded fuels into the fuel tank of a vehicle which cannot accept leaded fuels.
While there have been various systems in the prior art for providing one or more of the above system requirements, there is still much room for improvement, particularly with respect to saving weight and space, simplifying installation, crash worthiness and reducing costs (both cost of materials and installation labor). There is also additional room for improvement of operation during filling. More specifically, there is a problem with many present day fuel filling pipe systems which prevents the fuel tank from being filled at the maximum possible pumping rate, due to false triggering of the automatic shut-off mechanism. This problem is caused in part by fuel splash back and by the intercoupling of the vent mechanism with the fuel inlet passage. Also, while crash worthiness has been generally addressed within the industry, most so-called crash worthy fuel filling pipe systems simply employ breakaway filler neck tubes, permitting the filler tube to be severed from the gas tank upon impact. However, such breakaway designs do not adequately prevent fuel from leaking from the broken filler tube or gas tank after such a collision has occurred.
Accordingly, it is an object of the present invention to meet all of the above named fuel filling pipe design requirements, while overcoming the above problems found in the prior art. It is therefore an object of the invention to provide a more desirable and collision safe fuel filling pipe system which has a reduced size and weight, and simplified means for attachment between the automotive vehicle body and the gas tank. Yet another object of the invention is to provide a fuel filling pipe system which employs check valves at the gas tank to prevent leakage from the tank if the filling pipe system is ruptured, as during a collision.
A still further object of the invention is to provide a lower cost fuel filling pipe system which employs inexpensively manufactured and easily installed snap together plastic parts and flexible fuel piping. Through the use of such flexible piping and snap together components, the invention thus allows for better utilization of space within the automotive vehicle, making the invention ideal for use in smaller sized automobiles. The invention allows increased latitude in the location and routing of the fuel filling piping, which can result in lower overall costs and improved use of space for other automotive functional requirements.
Yet another object of the invention is to provide a more reliable fuel filling pipe system in which the venting system is isolated from the fuel filling pipe, so that fuel will not splash back and thereby block the venting system. This allows the automatic shut-off of the filling station nozzle to work with greater accuracy, thereby making it easier to precisely control the fill level in the tank. This results in the ability to utilize a smaller gas tank for the same fuel volume, by reducing the non-filled space within the tank.
In accordance with the invention a fuel filling pipe system is provided which employs a seal positioned to permit the filling of the fuel tank under pressure of the filling station fuel pump, while providing a positive seal so that fuel dispensed from the nozzle cannot enter the vent chamber. Also in accordance with the invention, the fuel tank is provided with a plurality of check valves, one associated with the fuel filling pipe, and the other associated with the venting system. These valves are normally held closed, so that fuel cannot leak from the tank even when the filling pipe has been broken or ruptured. The check valves are constructed to yield to the filling station fuel pump pressures, thereby permitting the introduction of fuel into the tank and the escape of air and vapors displaced by the incoming fuel.